Thisstory was updated at 7:44 p.m. EDT.
Astronauts aboardNASA?s space shuttle Discovery have to wait at least one more day beforereturning to Earth after thunderstorms and strong winds thwarted attempts toland Thursday.
Discoveryhad two chances to land at the Kennedy Space Center (KSC) in Florida Thursdayevening, but the stormy weather spoiled both tries. Thespace shuttle is now slated to land no earlier than Friday at 5:48p.m. EDT (2148 GMT), though weather conditions are expected to be even worse,NASA officials said.
?Theshowers we were hoping would die out ? it just doesn?t look like it?s comingtogether for us,? Mission Control radioed Discovery?s crew.
?We knoweverybody worked it as hard as they could and we?re looking forward to tryingit again tomorrow,? shuttle commander Rick Sturckow replied.
MissionControl said the weather situation in Florida was so dynamic that the decisionto call off the landing came ?down to the wire,? with just eight minutesremaining before Discovery was due to fire its engines to leave orbit.
The sevenastronauts aboard Discovery are returning home to cap what is now 14-daydelivery mission to the InternationalSpace Station. The shuttle has enough supplies to stay in orbit throughSunday, but entry flight director Richard Jones said he plans to land theshuttle by Saturday at the latest.
On Friday,Discovery?s crew has four opportunities to land, with two chances each in Floridaand at a backup runway at the Edwards Air Force Base in California.
?Thatsounds like a great forward plan,? Sturckow said.
But theweather outlook for Friday in Florida remains grim. More rain,thunderstorms and stiff winds are expected, Mission Control said. Forecasts forthe California runway are favorable.
NASA?sshuttle landing rules require no thunderstorms within about 30 miles (48 km) ofthe runaway to avoid flying through rain, which can damage an orbiter?s fragileheat shield tiles. Discovery is carrying a special heat shield tile with anintentional ?speed bump? as part of an unrelated experiment to study re-entryheating, mission managers said.
Beforetoday?s landing delay, Jones said he was hopeful Discovery would be able toreturn to its Florida home.
?I?d liketo stress we would like to go out as far as possible to go to KSC,? Jones saidWednesday while outlining his landing plans.
NASAprefers to land space shuttles in Florida whenever possible because it is theorbiter fleet?s home port. Florida landings avoid the extra week of transporttime and $1.8 million in turnaround costs required to ferry shuttles back fromCalifornia to be primed for the next mission. Discovery is due to fly to thespace station again early next year to deliver more supplies.
?There?re alot of good reasons that you want to make sure that you get into KSC,? Jonessaid.
Discoveryastronauts launchedlate Aug. 28 to deliver about 18,548 pounds (8,413 kg) of food, scienceequipment and other vital supplies to the space station. They performed threespacewalks to replace a massive coolant tank and replaced one member of thestation?s six-person crew. The big-ticket items on Discovery?s delivery listwere an air-scrubbing device, a pair of sophisticated science racks, a newastronaut bedroom and a treadmill named after TV comedian Stephen Colbert.
Colbert wonan online poll to have a new space station room named after him earlier thisyear, but NASA gave him the treadmill - known as the Combined Operational LoadBearing External Resistance Treadmill - instead. The agency named the new roomTranquility after the Apollo 11 moon base.
Thetreadmill is in more than 100 pieces, but won?t be assembled until after a newJapanese cargo ship arrives at the station Sept. 17. Japan launched theunmanned space freighter earlier today just hours ahead of Discovery?sattempted landings. NASA astronaut Nicole Stott, who flew to the station aboardDiscovery to join the station crew, will use the station?s robotic arm to pluckthe cargo ship from space once it arrives.
Stottreplaced fellow astronaut Tim Kopra as a member of the space station?s crew.Kopra is returning home after nearly two months in space, while Stott isbeginning what she plans to be a three-month space mission.
BuzzLightyear is also returning home aboard Discovery. The DisneySpace Ranger launched to the space station in May 2008 and spent 15 monthsin orbit as part of an educational project. The 12-inch toy from the film ?ToyStory? will be returned to the Walt Disney World in Florida, where he isexpected to be welcomed with a tickertape parade.
Earliertoday, Discovery had to fire its engines to dodge what Mission Control called?mystery orbital debris,? a piece of space junk that was expected to fly tooclose to the shuttle for comfort. The debris separated from either Discovery orthe space station on Saturday during a spacewalk, though NASA does not knowwhat the object is or its size.
Sturckowfired Discovery?s twin orbital maneuvering system engines to move the shuttleclear of the debris and it did not hamper the shuttle?s landing preparations.
Discovery?sSTS-128 mission is NASA?s fourth of up to five shuttle flights of 2009. NASAplans to launch six more shuttle missions after Discovery returns beforeretiring its three-orbiter fleet in the next year or so.
- Image Gallery - Shuttle Discovery's Midnight Launch
- Video - Stephen Colbert to NASA: 'No Chubby Astronauts'
- SPACE.com Video Show - The ISS: Foothold on Forever
SPACE.comis providing complete coverage of Discovery's STS-128 mission to theInternational Space Station with Managing Editor Tariq Malik and Staff WriterClara Moskowitz in New York. Clickhere for shuttle mission updates and a link to NASA TV.